xref: /freebsd/usr.bin/gprof/arcs.c (revision 6dced2c6358e467ac1dccd99f6f648d4f71957a8)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1983, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #if 0
33 #endif
34 
35 #include <sys/cdefs.h>
36 #include <err.h>
37 #include "gprof.h"
38 
39 #ifdef DEBUG
40 int visited;
41 int viable;
42 int newcycle;
43 int oldcycle;
44 #endif /* DEBUG */
45 
46 int topcmp(const void *, const void *);
47 
48     /*
49      *	add (or just increment) an arc
50      */
51 void
52 addarc(nltype *parentp, nltype *childp, long count)
53 {
54     arctype		*arcp;
55 
56 #   ifdef DEBUG
57 	if ( debug & TALLYDEBUG ) {
58 	    printf( "[addarc] %ld arcs from %s to %s\n" ,
59 		    count , parentp -> name , childp -> name );
60 	}
61 #   endif /* DEBUG */
62     arcp = arclookup( parentp , childp );
63     if ( arcp != 0 ) {
64 	    /*
65 	     *	a hit:  just increment the count.
66 	     */
67 #	ifdef DEBUG
68 	    if ( debug & TALLYDEBUG ) {
69 		printf( "[tally] hit %ld += %ld\n" ,
70 			arcp -> arc_count , count );
71 	    }
72 #	endif /* DEBUG */
73 	arcp -> arc_count += count;
74 	return;
75     }
76     arcp = (arctype *)calloc( 1 , sizeof *arcp );
77     if (arcp == NULL)
78 	errx( 1 , "malloc failed" );
79     arcp -> arc_parentp = parentp;
80     arcp -> arc_childp = childp;
81     arcp -> arc_count = count;
82 	/*
83 	 *	prepend this child to the children of this parent
84 	 */
85     arcp -> arc_childlist = parentp -> children;
86     parentp -> children = arcp;
87 	/*
88 	 *	prepend this parent to the parents of this child
89 	 */
90     arcp -> arc_parentlist = childp -> parents;
91     childp -> parents = arcp;
92 }
93 
94     /*
95      *	the code below topologically sorts the graph (collapsing cycles),
96      *	and propagates time bottom up and flags top down.
97      */
98 
99     /*
100      *	the topologically sorted name list pointers
101      */
102 nltype	**topsortnlp;
103 
104 int
105 topcmp(const void *v1, const void *v2)
106 {
107     const nltype **npp1 = (const nltype **)v1;
108     const nltype **npp2 = (const nltype **)v2;
109 
110     return (*npp1) -> toporder - (*npp2) -> toporder;
111 }
112 
113 nltype **
114 doarcs(void)
115 {
116     nltype	*parentp, **timesortnlp;
117     arctype	*arcp;
118     long	index;
119     long	pass;
120 
121 	/*
122 	 *	initialize various things:
123 	 *	    zero out child times.
124 	 *	    count self-recursive calls.
125 	 *	    indicate that nothing is on cycles.
126 	 */
127     for ( parentp = nl ; parentp < npe ; parentp++ ) {
128 	parentp -> childtime = 0.0;
129 	arcp = arclookup( parentp , parentp );
130 	if ( arcp != 0 ) {
131 	    parentp -> ncall -= arcp -> arc_count;
132 	    parentp -> selfcalls = arcp -> arc_count;
133 	} else {
134 	    parentp -> selfcalls = 0;
135 	}
136 	parentp -> npropcall = parentp -> ncall;
137 	parentp -> propfraction = 0.0;
138 	parentp -> propself = 0.0;
139 	parentp -> propchild = 0.0;
140 	parentp -> printflag = FALSE;
141 	parentp -> toporder = DFN_NAN;
142 	parentp -> cycleno = 0;
143 	parentp -> cyclehead = parentp;
144 	parentp -> cnext = 0;
145     }
146     for ( pass = 1 ; ; pass++ ) {
147 	    /*
148 	     *	topologically order things
149 	     *	if any node is unnumbered,
150 	     *	    number it and any of its descendents.
151 	     */
152 	for ( dfn_init() , parentp = nl ; parentp < npe ; parentp++ ) {
153 	    if ( parentp -> toporder == DFN_NAN ) {
154 		dfn( parentp );
155 	    }
156 	}
157 	    /*
158 	     *	link together nodes on the same cycle
159 	     */
160 	cyclelink();
161 	    /*
162 	     *	if no cycles to break up, proceed
163 	     */
164 	if ( ! Cflag )
165 	    break;
166 	    /*
167 	     *	analyze cycles to determine breakup
168 	     */
169 #	ifdef DEBUG
170 	    if ( debug & BREAKCYCLE ) {
171 		printf("[doarcs] pass %ld, cycle(s) %d\n" , pass , ncycle );
172 	    }
173 #	endif /* DEBUG */
174 	if ( pass == 1 ) {
175 	    printf( "\n\n%s %s\n%s %d:\n" ,
176 		"The following arcs were deleted" ,
177 		"from the propagation calculation" ,
178 		"to reduce the maximum cycle size to", cyclethreshold );
179 	}
180 	if ( cycleanalyze() )
181 	    break;
182 	free ( cyclenl );
183 	ncycle = 0;
184 	for ( parentp = nl ; parentp < npe ; parentp++ ) {
185 	    parentp -> toporder = DFN_NAN;
186 	    parentp -> cycleno = 0;
187 	    parentp -> cyclehead = parentp;
188 	    parentp -> cnext = 0;
189 	}
190     }
191     if ( pass > 1 ) {
192 	printf( "\f\n" );
193     } else {
194 	printf( "\tNone\n\n" );
195     }
196 	/*
197 	 *	Sort the symbol table in reverse topological order
198 	 */
199     topsortnlp = (nltype **) calloc( nname , sizeof(nltype *) );
200     if ( topsortnlp == (nltype **) 0 )
201 	errx( 1 , "[doarcs] ran out of memory for topo sorting" );
202     for ( index = 0 ; index < nname ; index += 1 ) {
203 	topsortnlp[ index ] = &nl[ index ];
204     }
205     qsort( topsortnlp , nname , sizeof(nltype *) , topcmp );
206 #   ifdef DEBUG
207 	if ( debug & DFNDEBUG ) {
208 	    printf( "[doarcs] topological sort listing\n" );
209 	    for ( index = 0 ; index < nname ; index += 1 ) {
210 		printf( "[doarcs] " );
211 		printf( "%d:" , topsortnlp[ index ] -> toporder );
212 		printname( topsortnlp[ index ] );
213 		printf( "\n" );
214 	    }
215 	}
216 #   endif /* DEBUG */
217 	/*
218 	 *	starting from the topological top,
219 	 *	propagate print flags to children.
220 	 *	also, calculate propagation fractions.
221 	 *	this happens before time propagation
222 	 *	since time propagation uses the fractions.
223 	 */
224     doflags();
225 	/*
226 	 *	starting from the topological bottom,
227 	 *	propagate children times up to parents.
228 	 */
229     dotime();
230 	/*
231 	 *	Now, sort by propself + propchild.
232 	 *	sorting both the regular function names
233 	 *	and cycle headers.
234 	 */
235     timesortnlp = (nltype **) calloc( nname + ncycle , sizeof(nltype *) );
236     if ( timesortnlp == (nltype **) 0 )
237 	errx( 1 , "ran out of memory for sorting" );
238     for ( index = 0 ; index < nname ; index++ ) {
239 	timesortnlp[index] = &nl[index];
240     }
241     for ( index = 1 ; index <= ncycle ; index++ ) {
242 	timesortnlp[nname+index-1] = &cyclenl[index];
243     }
244     qsort( timesortnlp , nname + ncycle , sizeof(nltype *) , totalcmp );
245     for ( index = 0 ; index < nname + ncycle ; index++ ) {
246 	timesortnlp[ index ] -> index = index + 1;
247     }
248     return( timesortnlp );
249 }
250 
251 void
252 dotime(void)
253 {
254     int	index;
255 
256     cycletime();
257     for ( index = 0 ; index < nname ; index += 1 ) {
258 	timepropagate( topsortnlp[ index ] );
259     }
260 }
261 
262 void
263 timepropagate(nltype *parentp)
264 {
265     arctype	*arcp;
266     nltype	*childp;
267     double	share;
268     double	propshare;
269 
270     if ( parentp -> propfraction == 0.0 ) {
271 	return;
272     }
273 	/*
274 	 *	gather time from children of this parent.
275 	 */
276     for ( arcp = parentp -> children ; arcp ; arcp = arcp -> arc_childlist ) {
277 	childp = arcp -> arc_childp;
278 	if ( arcp -> arc_flags & DEADARC ) {
279 	    continue;
280 	}
281 	if ( arcp -> arc_count == 0 ) {
282 	    continue;
283 	}
284 	if ( childp == parentp ) {
285 	    continue;
286 	}
287 	if ( childp -> propfraction == 0.0 ) {
288 	    continue;
289 	}
290 	if ( childp -> cyclehead != childp ) {
291 	    if ( parentp -> cycleno == childp -> cycleno ) {
292 		continue;
293 	    }
294 	    if ( parentp -> toporder <= childp -> toporder ) {
295 		fprintf( stderr , "[propagate] toporder botches\n" );
296 	    }
297 	    childp = childp -> cyclehead;
298 	} else {
299 	    if ( parentp -> toporder <= childp -> toporder ) {
300 		fprintf( stderr , "[propagate] toporder botches\n" );
301 		continue;
302 	    }
303 	}
304 	if ( childp -> npropcall == 0 ) {
305 	    continue;
306 	}
307 	    /*
308 	     *	distribute time for this arc
309 	     */
310 	arcp -> arc_time = childp -> time
311 			        * ( ( (double) arcp -> arc_count ) /
312 				    ( (double) childp -> npropcall ) );
313 	arcp -> arc_childtime = childp -> childtime
314 			        * ( ( (double) arcp -> arc_count ) /
315 				    ( (double) childp -> npropcall ) );
316 	share = arcp -> arc_time + arcp -> arc_childtime;
317 	parentp -> childtime += share;
318 	    /*
319 	     *	( 1 - propfraction ) gets lost along the way
320 	     */
321 	propshare = parentp -> propfraction * share;
322 	    /*
323 	     *	fix things for printing
324 	     */
325 	parentp -> propchild += propshare;
326 	arcp -> arc_time *= parentp -> propfraction;
327 	arcp -> arc_childtime *= parentp -> propfraction;
328 	    /*
329 	     *	add this share to the parent's cycle header, if any.
330 	     */
331 	if ( parentp -> cyclehead != parentp ) {
332 	    parentp -> cyclehead -> childtime += share;
333 	    parentp -> cyclehead -> propchild += propshare;
334 	}
335 #	ifdef DEBUG
336 	    if ( debug & PROPDEBUG ) {
337 		printf( "[dotime] child \t" );
338 		printname( childp );
339 		printf( " with %f %f %ld/%ld\n" ,
340 			childp -> time , childp -> childtime ,
341 			arcp -> arc_count , childp -> npropcall );
342 		printf( "[dotime] parent\t" );
343 		printname( parentp );
344 		printf( "\n[dotime] share %f\n" , share );
345 	    }
346 #	endif /* DEBUG */
347     }
348 }
349 
350 void
351 cyclelink(void)
352 {
353     register nltype	*nlp;
354     register nltype	*cyclenlp;
355     int			cycle;
356     nltype		*memberp;
357     arctype		*arcp;
358 
359 	/*
360 	 *	Count the number of cycles, and initialize the cycle lists
361 	 */
362     ncycle = 0;
363     for ( nlp = nl ; nlp < npe ; nlp++ ) {
364 	    /*
365 	     *	this is how you find unattached cycles
366 	     */
367 	if ( nlp -> cyclehead == nlp && nlp -> cnext != 0 ) {
368 	    ncycle += 1;
369 	}
370     }
371 	/*
372 	 *	cyclenl is indexed by cycle number:
373 	 *	i.e. it is origin 1, not origin 0.
374 	 */
375     cyclenl = (nltype *) calloc( ncycle + 1 , sizeof( nltype ) );
376     if ( cyclenl == NULL )
377 	errx( 1 , "no room for %zu bytes of cycle headers" ,
378 		   ( ncycle + 1 ) * sizeof( nltype ) );
379 	/*
380 	 *	now link cycles to true cycleheads,
381 	 *	number them, accumulate the data for the cycle
382 	 */
383     cycle = 0;
384     for ( nlp = nl ; nlp < npe ; nlp++ ) {
385 	if ( !( nlp -> cyclehead == nlp && nlp -> cnext != 0 ) ) {
386 	    continue;
387 	}
388 	cycle += 1;
389 	cyclenlp = &cyclenl[cycle];
390         cyclenlp -> name = 0;		/* the name */
391         cyclenlp -> value = 0;		/* the pc entry point */
392         cyclenlp -> time = 0.0;		/* ticks in this routine */
393         cyclenlp -> childtime = 0.0;	/* cumulative ticks in children */
394 	cyclenlp -> ncall = 0;		/* how many times called */
395 	cyclenlp -> selfcalls = 0;	/* how many calls to self */
396 	cyclenlp -> propfraction = 0.0;	/* what % of time propagates */
397 	cyclenlp -> propself = 0.0;	/* how much self time propagates */
398 	cyclenlp -> propchild = 0.0;	/* how much child time propagates */
399 	cyclenlp -> printflag = TRUE;	/* should this be printed? */
400 	cyclenlp -> index = 0;		/* index in the graph list */
401 	cyclenlp -> toporder = DFN_NAN;	/* graph call chain top-sort order */
402 	cyclenlp -> cycleno = cycle;	/* internal number of cycle on */
403 	cyclenlp -> cyclehead = cyclenlp;	/* pointer to head of cycle */
404 	cyclenlp -> cnext = nlp;	/* pointer to next member of cycle */
405 	cyclenlp -> parents = 0;	/* list of caller arcs */
406 	cyclenlp -> children = 0;	/* list of callee arcs */
407 #	ifdef DEBUG
408 	    if ( debug & CYCLEDEBUG ) {
409 		printf( "[cyclelink] " );
410 		printname( nlp );
411 		printf( " is the head of cycle %d\n" , cycle );
412 	    }
413 #	endif /* DEBUG */
414 	    /*
415 	     *	link members to cycle header
416 	     */
417 	for ( memberp = nlp ; memberp ; memberp = memberp -> cnext ) {
418 	    memberp -> cycleno = cycle;
419 	    memberp -> cyclehead = cyclenlp;
420 	}
421 	    /*
422 	     *	count calls from outside the cycle
423 	     *	and those among cycle members
424 	     */
425 	for ( memberp = nlp ; memberp ; memberp = memberp -> cnext ) {
426 	    for ( arcp=memberp->parents ; arcp ; arcp=arcp->arc_parentlist ) {
427 		if ( arcp -> arc_parentp == memberp ) {
428 		    continue;
429 		}
430 		if ( arcp -> arc_parentp -> cycleno == cycle ) {
431 		    cyclenlp -> selfcalls += arcp -> arc_count;
432 		} else {
433 		    cyclenlp -> npropcall += arcp -> arc_count;
434 		}
435 	    }
436 	}
437     }
438 }
439 
440     /*
441      *	analyze cycles to determine breakup
442      */
443 bool
444 cycleanalyze(void)
445 {
446     arctype	**cyclestack;
447     arctype	**stkp;
448     arctype	**arcpp;
449     arctype	**endlist;
450     arctype	*arcp;
451     nltype	*nlp;
452     cltype	*clp;
453     bool	ret;
454     bool	done;
455     int		size;
456     int		cycleno;
457 
458 	/*
459 	 *	calculate the size of the cycle, and find nodes that
460 	 *	exit the cycle as they are desirable targets to cut
461 	 *	some of their parents
462 	 */
463     for ( done = TRUE , cycleno = 1 ; cycleno <= ncycle ; cycleno++ ) {
464 	size = 0;
465 	for (nlp = cyclenl[ cycleno ] . cnext; nlp; nlp = nlp -> cnext) {
466 	    size += 1;
467 	    nlp -> parentcnt = 0;
468 	    nlp -> flags &= ~HASCYCLEXIT;
469 	    for ( arcp = nlp -> parents; arcp; arcp = arcp -> arc_parentlist ) {
470 		nlp -> parentcnt += 1;
471 		if ( arcp -> arc_parentp -> cycleno != cycleno )
472 		    nlp -> flags |= HASCYCLEXIT;
473 	    }
474 	}
475 	if ( size <= cyclethreshold )
476 	    continue;
477 	done = FALSE;
478         cyclestack = (arctype **) calloc( size + 1 , sizeof( arctype *) );
479 	if ( cyclestack == NULL )
480 	    errx( 1, "no room for %zu bytes of cycle stack" ,
481 			   ( size + 1 ) * sizeof( arctype * ) );
482 #	ifdef DEBUG
483 	    if ( debug & BREAKCYCLE ) {
484 		printf( "[cycleanalyze] starting cycle %d of %d, size %d\n" ,
485 		    cycleno , ncycle , size );
486 	    }
487 #	endif /* DEBUG */
488 	for ( nlp = cyclenl[ cycleno ] . cnext ; nlp ; nlp = nlp -> cnext ) {
489 	    stkp = &cyclestack[0];
490 	    nlp -> flags |= CYCLEHEAD;
491 	    ret = descend ( nlp , cyclestack , stkp );
492 	    nlp -> flags &= ~CYCLEHEAD;
493 	    if ( ret == FALSE )
494 		break;
495 	}
496 	free( cyclestack );
497 	if ( cyclecnt > 0 ) {
498 	    compresslist();
499 	    for ( clp = cyclehead ; clp ; ) {
500 		endlist = &clp -> list[ clp -> size ];
501 		for ( arcpp = clp -> list ; arcpp < endlist ; arcpp++ )
502 		    (*arcpp) -> arc_cyclecnt--;
503 		cyclecnt--;
504 		clp = clp -> next;
505 		free( clp );
506 	    }
507 	    cyclehead = 0;
508 	}
509     }
510 #   ifdef DEBUG
511 	if ( debug & BREAKCYCLE ) {
512 	    printf("%s visited %d, viable %d, newcycle %d, oldcycle %d\n",
513 		"[doarcs]" , visited , viable , newcycle , oldcycle);
514 	}
515 #   endif /* DEBUG */
516     return( done );
517 }
518 
519 bool
520 descend(nltype *node, arctype **stkstart, arctype **stkp)
521 {
522     arctype	*arcp;
523     bool	ret;
524 
525     for ( arcp = node -> children ; arcp ; arcp = arcp -> arc_childlist ) {
526 #	ifdef DEBUG
527 	    visited++;
528 #	endif /* DEBUG */
529 	if ( arcp -> arc_childp -> cycleno != node -> cycleno
530 	    || ( arcp -> arc_childp -> flags & VISITED )
531 	    || ( arcp -> arc_flags & DEADARC ) )
532 	    continue;
533 #	ifdef DEBUG
534 	    viable++;
535 #	endif /* DEBUG */
536 	*stkp = arcp;
537 	if ( arcp -> arc_childp -> flags & CYCLEHEAD ) {
538 	    if ( addcycle( stkstart , stkp ) == FALSE )
539 		return( FALSE );
540 	    continue;
541 	}
542 	arcp -> arc_childp -> flags |= VISITED;
543 	ret = descend( arcp -> arc_childp , stkstart , stkp + 1 );
544 	arcp -> arc_childp -> flags &= ~VISITED;
545 	if ( ret == FALSE )
546 	    return( FALSE );
547     }
548     return( TRUE );
549 }
550 
551 bool
552 addcycle(arctype **stkstart, arctype **stkend)
553 {
554     arctype	**arcpp;
555     arctype	**stkloc;
556     arctype	**stkp;
557     arctype	**endlist;
558     arctype	*minarc;
559     arctype	*arcp;
560     cltype	*clp;
561     int		size;
562 
563     size = stkend - stkstart + 1;
564     if ( size <= 1 )
565 	return( TRUE );
566     for ( arcpp = stkstart , minarc = *arcpp ; arcpp <= stkend ; arcpp++ ) {
567 	if ( *arcpp > minarc )
568 	    continue;
569 	minarc = *arcpp;
570 	stkloc = arcpp;
571     }
572     for ( clp = cyclehead ; clp ; clp = clp -> next ) {
573 	if ( clp -> size != size )
574 	    continue;
575 	stkp = stkloc;
576 	endlist = &clp -> list[ size ];
577 	for ( arcpp = clp -> list ; arcpp < endlist ; arcpp++ ) {
578 	    if ( *stkp++ != *arcpp )
579 		break;
580 	    if ( stkp > stkend )
581 		stkp = stkstart;
582 	}
583 	if ( arcpp == endlist ) {
584 #	    ifdef DEBUG
585 		oldcycle++;
586 #	    endif /* DEBUG */
587 	    return( TRUE );
588 	}
589     }
590     clp = (cltype *)
591 	calloc( 1 , sizeof ( cltype ) + ( size - 1 ) * sizeof( arctype * ) );
592     if ( clp == NULL ) {
593 	warnx( "no room for %zu bytes of subcycle storage" ,
594 	    sizeof ( cltype ) + ( size - 1 ) * sizeof( arctype * ) );
595 	return( FALSE );
596     }
597     stkp = stkloc;
598     endlist = &clp -> list[ size ];
599     for ( arcpp = clp -> list ; arcpp < endlist ; arcpp++ ) {
600 	arcp = *arcpp = *stkp++;
601 	if ( stkp > stkend )
602 	    stkp = stkstart;
603 	arcp -> arc_cyclecnt++;
604 	if ( ( arcp -> arc_flags & ONLIST ) == 0 ) {
605 	    arcp -> arc_flags |= ONLIST;
606 	    arcp -> arc_next = archead;
607 	    archead = arcp;
608 	}
609     }
610     clp -> size = size;
611     clp -> next = cyclehead;
612     cyclehead = clp;
613 #   ifdef DEBUG
614 	newcycle++;
615 	if ( debug & SUBCYCLELIST ) {
616 	    printsubcycle( clp );
617 	}
618 #   endif /* DEBUG */
619     cyclecnt++;
620     if ( cyclecnt >= CYCLEMAX )
621 	return( FALSE );
622     return( TRUE );
623 }
624 
625 void
626 compresslist(void)
627 {
628     cltype	*clp;
629     cltype	**prev;
630     arctype	**arcpp;
631     arctype	**endlist;
632     arctype	*arcp;
633     arctype	*maxarcp;
634     arctype	*maxexitarcp;
635     arctype	*maxwithparentarcp;
636     arctype	*maxnoparentarcp;
637     int		maxexitcnt;
638     int		maxwithparentcnt;
639     int		maxnoparentcnt;
640 #   ifdef DEBUG
641 	const char	*type;
642 #   endif /* DEBUG */
643 
644     maxexitcnt = 0;
645     maxwithparentcnt = 0;
646     maxnoparentcnt = 0;
647     for ( endlist = &archead , arcp = archead ; arcp ; ) {
648 	if ( arcp -> arc_cyclecnt == 0 ) {
649 	    arcp -> arc_flags &= ~ONLIST;
650 	    *endlist = arcp -> arc_next;
651 	    arcp -> arc_next = 0;
652 	    arcp = *endlist;
653 	    continue;
654 	}
655 	if ( arcp -> arc_childp -> flags & HASCYCLEXIT ) {
656 	    if ( arcp -> arc_cyclecnt > maxexitcnt ||
657 		( arcp -> arc_cyclecnt == maxexitcnt &&
658 		arcp -> arc_cyclecnt < maxexitarcp -> arc_count ) ) {
659 		maxexitcnt = arcp -> arc_cyclecnt;
660 		maxexitarcp = arcp;
661 	    }
662 	} else if ( arcp -> arc_childp -> parentcnt > 1 ) {
663 	    if ( arcp -> arc_cyclecnt > maxwithparentcnt ||
664 		( arcp -> arc_cyclecnt == maxwithparentcnt &&
665 		arcp -> arc_cyclecnt < maxwithparentarcp -> arc_count ) ) {
666 		maxwithparentcnt = arcp -> arc_cyclecnt;
667 		maxwithparentarcp = arcp;
668 	    }
669 	} else {
670 	    if ( arcp -> arc_cyclecnt > maxnoparentcnt ||
671 		( arcp -> arc_cyclecnt == maxnoparentcnt &&
672 		arcp -> arc_cyclecnt < maxnoparentarcp -> arc_count ) ) {
673 		maxnoparentcnt = arcp -> arc_cyclecnt;
674 		maxnoparentarcp = arcp;
675 	    }
676 	}
677 	endlist = &arcp -> arc_next;
678 	arcp = arcp -> arc_next;
679     }
680     if ( maxexitcnt > 0 ) {
681 	/*
682 	 *	first choice is edge leading to node with out-of-cycle parent
683 	 */
684 	maxarcp = maxexitarcp;
685 #	ifdef DEBUG
686 	    type = "exit";
687 #	endif /* DEBUG */
688     } else if ( maxwithparentcnt > 0 ) {
689 	/*
690 	 *	second choice is edge leading to node with at least one
691 	 *	other in-cycle parent
692 	 */
693 	maxarcp = maxwithparentarcp;
694 #	ifdef DEBUG
695 	    type = "internal";
696 #	endif /* DEBUG */
697     } else {
698 	/*
699 	 *	last choice is edge leading to node with only this arc as
700 	 *	a parent (as it will now be orphaned)
701 	 */
702 	maxarcp = maxnoparentarcp;
703 #	ifdef DEBUG
704 	    type = "orphan";
705 #	endif /* DEBUG */
706     }
707     maxarcp -> arc_flags |= DEADARC;
708     maxarcp -> arc_childp -> parentcnt -= 1;
709     maxarcp -> arc_childp -> npropcall -= maxarcp -> arc_count;
710 #   ifdef DEBUG
711 	if ( debug & BREAKCYCLE ) {
712 	    printf( "%s delete %s arc: %s (%ld) -> %s from %u cycle(s)\n" ,
713 		"[compresslist]" , type , maxarcp -> arc_parentp -> name ,
714 		maxarcp -> arc_count , maxarcp -> arc_childp -> name ,
715 		maxarcp -> arc_cyclecnt );
716 	}
717 #   endif /* DEBUG */
718     printf( "\t%s to %s with %ld calls\n" , maxarcp -> arc_parentp -> name ,
719 	maxarcp -> arc_childp -> name , maxarcp -> arc_count );
720     prev = &cyclehead;
721     for ( clp = cyclehead ; clp ; ) {
722 	endlist = &clp -> list[ clp -> size ];
723 	for ( arcpp = clp -> list ; arcpp < endlist ; arcpp++ )
724 	    if ( (*arcpp) -> arc_flags & DEADARC )
725 		break;
726 	if ( arcpp == endlist ) {
727 	    prev = &clp -> next;
728 	    clp = clp -> next;
729 	    continue;
730 	}
731 	for ( arcpp = clp -> list ; arcpp < endlist ; arcpp++ )
732 	    (*arcpp) -> arc_cyclecnt--;
733 	cyclecnt--;
734 	*prev = clp -> next;
735 	clp = clp -> next;
736 	free( clp );
737     }
738 }
739 
740 #ifdef DEBUG
741 void
742 printsubcycle(cltype *clp)
743 {
744     arctype	**arcpp;
745     arctype	**endlist;
746 
747     arcpp = clp -> list;
748     printf( "%s <cycle %d>\n" , (*arcpp) -> arc_parentp -> name ,
749 	(*arcpp) -> arc_parentp -> cycleno ) ;
750     for ( endlist = &clp -> list[ clp -> size ]; arcpp < endlist ; arcpp++ )
751 	printf( "\t(%ld) -> %s\n" , (*arcpp) -> arc_count ,
752 	    (*arcpp) -> arc_childp -> name ) ;
753 }
754 #endif /* DEBUG */
755 
756 void
757 cycletime(void)
758 {
759     int			cycle;
760     nltype		*cyclenlp;
761     nltype		*childp;
762 
763     for ( cycle = 1 ; cycle <= ncycle ; cycle += 1 ) {
764 	cyclenlp = &cyclenl[ cycle ];
765 	for ( childp = cyclenlp -> cnext ; childp ; childp = childp -> cnext ) {
766 	    if ( childp -> propfraction == 0.0 ) {
767 		    /*
768 		     * all members have the same propfraction except those
769 		     *	that were excluded with -E
770 		     */
771 		continue;
772 	    }
773 	    cyclenlp -> time += childp -> time;
774 	}
775 	cyclenlp -> propself = cyclenlp -> propfraction * cyclenlp -> time;
776     }
777 }
778 
779     /*
780      *	in one top to bottom pass over the topologically sorted namelist
781      *	propagate:
782      *		printflag as the union of parents' printflags
783      *		propfraction as the sum of fractional parents' propfractions
784      *	and while we're here, sum time for functions.
785      */
786 void
787 doflags(void)
788 {
789     int		index;
790     nltype	*childp;
791     nltype	*oldhead;
792 
793     oldhead = 0;
794     for ( index = nname-1 ; index >= 0 ; index -= 1 ) {
795 	childp = topsortnlp[ index ];
796 	    /*
797 	     *	if we haven't done this function or cycle,
798 	     *	inherit things from parent.
799 	     *	this way, we are linear in the number of arcs
800 	     *	since we do all members of a cycle (and the cycle itself)
801 	     *	as we hit the first member of the cycle.
802 	     */
803 	if ( childp -> cyclehead != oldhead ) {
804 	    oldhead = childp -> cyclehead;
805 	    inheritflags( childp );
806 	}
807 #	ifdef DEBUG
808 	    if ( debug & PROPDEBUG ) {
809 		printf( "[doflags] " );
810 		printname( childp );
811 		printf( " inherits printflag %d and propfraction %f\n" ,
812 			childp -> printflag , childp -> propfraction );
813 	    }
814 #	endif /* DEBUG */
815 	if ( ! childp -> printflag ) {
816 		/*
817 		 *	printflag is off
818 		 *	it gets turned on by
819 		 *	being on -f list,
820 		 *	or there not being any -f list and not being on -e list.
821 		 */
822 	    if (   onlist( flist , childp -> name )
823 		|| ( !fflag && !onlist( elist , childp -> name ) ) ) {
824 		childp -> printflag = TRUE;
825 	    }
826 	} else {
827 		/*
828 		 *	this function has printing parents:
829 		 *	maybe someone wants to shut it up
830 		 *	by putting it on -e list.  (but favor -f over -e)
831 		 */
832 	    if (  ( !onlist( flist , childp -> name ) )
833 		&& onlist( elist , childp -> name ) ) {
834 		childp -> printflag = FALSE;
835 	    }
836 	}
837 	if ( childp -> propfraction == 0.0 ) {
838 		/*
839 		 *	no parents to pass time to.
840 		 *	collect time from children if
841 		 *	its on -F list,
842 		 *	or there isn't any -F list and its not on -E list.
843 		 */
844 	    if ( onlist( Flist , childp -> name )
845 		|| ( !Fflag && !onlist( Elist , childp -> name ) ) ) {
846 		    childp -> propfraction = 1.0;
847 	    }
848 	} else {
849 		/*
850 		 *	it has parents to pass time to,
851 		 *	but maybe someone wants to shut it up
852 		 *	by putting it on -E list.  (but favor -F over -E)
853 		 */
854 	    if (  !onlist( Flist , childp -> name )
855 		&& onlist( Elist , childp -> name ) ) {
856 		childp -> propfraction = 0.0;
857 	    }
858 	}
859 	childp -> propself = childp -> time * childp -> propfraction;
860 	printtime += childp -> propself;
861 #	ifdef DEBUG
862 	    if ( debug & PROPDEBUG ) {
863 		printf( "[doflags] " );
864 		printname( childp );
865 		printf( " ends up with printflag %d and propfraction %f\n" ,
866 			childp -> printflag , childp -> propfraction );
867 		printf( "time %f propself %f printtime %f\n" ,
868 			childp -> time , childp -> propself , printtime );
869 	    }
870 #	endif /* DEBUG */
871     }
872 }
873 
874     /*
875      *	check if any parent of this child
876      *	(or outside parents of this cycle)
877      *	have their print flags on and set the
878      *	print flag of the child (cycle) appropriately.
879      *	similarly, deal with propagation fractions from parents.
880      */
881 void
882 inheritflags(nltype *childp)
883 {
884     nltype	*headp;
885     arctype	*arcp;
886     nltype	*parentp;
887     nltype	*memp;
888 
889     headp = childp -> cyclehead;
890     if ( childp == headp ) {
891 	    /*
892 	     *	just a regular child, check its parents
893 	     */
894 	childp -> printflag = FALSE;
895 	childp -> propfraction = 0.0;
896 	for (arcp = childp -> parents ; arcp ; arcp = arcp -> arc_parentlist) {
897 	    parentp = arcp -> arc_parentp;
898 	    if ( childp == parentp ) {
899 		continue;
900 	    }
901 	    childp -> printflag |= parentp -> printflag;
902 		/*
903 		 *	if the child was never actually called
904 		 *	(e.g. this arc is static (and all others are, too))
905 		 *	no time propagates along this arc.
906 		 */
907 	    if ( arcp -> arc_flags & DEADARC ) {
908 		continue;
909 	    }
910 	    if ( childp -> npropcall ) {
911 		childp -> propfraction += parentp -> propfraction
912 					* ( ( (double) arcp -> arc_count )
913 					  / ( (double) childp -> npropcall ) );
914 	    }
915 	}
916     } else {
917 	    /*
918 	     *	its a member of a cycle, look at all parents from
919 	     *	outside the cycle
920 	     */
921 	headp -> printflag = FALSE;
922 	headp -> propfraction = 0.0;
923 	for ( memp = headp -> cnext ; memp ; memp = memp -> cnext ) {
924 	    for (arcp = memp->parents ; arcp ; arcp = arcp->arc_parentlist) {
925 		if ( arcp -> arc_parentp -> cyclehead == headp ) {
926 		    continue;
927 		}
928 		parentp = arcp -> arc_parentp;
929 		headp -> printflag |= parentp -> printflag;
930 		    /*
931 		     *	if the cycle was never actually called
932 		     *	(e.g. this arc is static (and all others are, too))
933 		     *	no time propagates along this arc.
934 		     */
935 		if ( arcp -> arc_flags & DEADARC ) {
936 		    continue;
937 		}
938 		if ( headp -> npropcall ) {
939 		    headp -> propfraction += parentp -> propfraction
940 					* ( ( (double) arcp -> arc_count )
941 					  / ( (double) headp -> npropcall ) );
942 		}
943 	    }
944 	}
945 	for ( memp = headp ; memp ; memp = memp -> cnext ) {
946 	    memp -> printflag = headp -> printflag;
947 	    memp -> propfraction = headp -> propfraction;
948 	}
949     }
950 }
951